Electrical connector assemblies of the locking type are well-known in the connector industry. Normally, the female portion of such a connector assembly has two or more arcuate, circularly arranged slots, and the male portion has an equal number of arcuate blades, the blades being dimensioned and arranged so that they can be inserted in the slots by a simple axial movement, and then, via rotation of one or both of the connector portions, the blades can be moved into a position from which they cannot be separated by simple axial movement. To accomplish this, one or more of the blades usually has an L-shaped configuration in which the laterally extending portion, or flag, of the blade engages a recess or shelf within the slot as a result of the rotation.
The male and female portions can take various configurations, but the male portion is usually a plug connected to the end of a multi-conductor cable. The female portion may also terminate a similar cable, or it can be a fixture or receptacle mounted in a partition or on a piece of equipment. In any event, it is possible for the cable attached to the male portion to be subjected to various forces which might tend to rotate the cable and also the male connector portion in the unlocking direction, thereby causing inadvertent unlocking and extraction of the blades from the slots.
To prevent this kind of undesired extraction, there has been an effort to develop connectors which have greater resistance to accidental disconnection or which have locking devices capable of precluding such accidental disconnection. However, many of these prior art devices are complicated to manufacture, assemble and use, and many of them require a significant number of parts and a specially designed female device to cooperate with the male device.
In addition, many of these electrical connector assemblies have some sort of shield which temporarily covers the blades during shipping or handling to protect the blades against distortion and to protect the installer from contacting the blades during installation. However, once again, many of these devices are unduly complicated to manufacture, assemble and use, and require numerous parts.
Moreover, there has recently been enacted by the Occupational Safety and Health Administration (OSHA) various regulations requiring specific mechanisms for preventing inadvertent connection of electrical connectors. These regulations require some sort of mechanism for locking out the electrical connector to avoid its inadvertent connection while, for example, the electrical device is being worked on.
Examples of various locking connectors are disclosed in the following U.S. Pat Nos.: 2,684,860 to Rafferty; 2,750,571 to Schmier; 3,120,987 to Degnan et al.; 3,390,404 to Murchison; 3,393,395 to Hubbell; 3,500,291 to Hubbell et al; 3,739,321 to Murphy et al; 3,790,914 to Hough; 3,888,559 to Geib; 3,890,025 to Gray; 3,950,059 to Anhalt et al; and 4,241,969 to D'Amato et al. Similar devices are disclosed in Italian patent 486174 and U.K. patent 500653.
In addition, examples of prior devices providing shields for the blades of electrical connectors are disclosed in the following U.S. Pat. Nos.: 2,396,901 to Tiffany; 2,423,250 to Modrey; 3,754,205 to Lenkey; 4,340,267 to Nukaga; 4,445,739 to Wooten; and 4,820,176 to Niikura.